No one's recommended Islands? I've only ever heard them live, and only once as an opener for Metric, but I'm fairly sure they'd be agreeable to an Arcade Fire fan. Architecture in Helsinki, though they have a fairly different 'sound' there are funny similarities in their song writing, and when I listen to The Arcade Fire, I find myself wanting to listen to Architecture in Helsinki later.
You could try
last fm for similar artists, but that system isn't exactly perfect. You will at least find some good sounding stuff, and if you look a little farther into the lists you may find something you like more.
Ticket prices are gross, but they can charge them, and big venues cost lots of money, if only due to the fact that whoever owns those massive concert halls can make more money off of someone who is willing to gouge. When you get big, that's the way it is. I doubt I'll ever see them live again unless it's a decent price and/or an awesome venue.
Have I told my story of that one festival two years ago that I like to talk about a lot? The time when, after a day of amazing bands I won't list, they came out and did a spectacular set, rocked out to an insane degree, with me close enough to the stage to actually hear the helmets the dude was bashing on. And then at 11:00 when the law said they had to shut down, they started playing "Wake Up", then one by one, hopped off of the stage, instruments in hand, and marched all around the park in a dozen different interweaving chains of concert-goers, chanting the recurring 'ohhhs' over and over.
Brilliant. Though I do talk about that weekend far too much, even two years later.